[octavmandru]

how long is a single flash pop? For the max exposure time, say on a 540?
I'm interested as approx. value, compared to the time the shutter gap needs to travel through the frame (about 1/200 on Pentax, right?).

[kittykat46]

how long is a single flash pop? For the max exposure time, say on a 540?
I'm interested as approx. value, compared to the time the shutter gap needs to travel through the frame (about 1/200 on Pentax, right?).

I've not seen any flash brand publish the actual timing for a single flash, but I was quoted a figure for the thyristors which power a well known brand of flash - and it triggers at 20 microseconds. That's 1/50,000 seconds. The actual flash strobe needs a bit of time to brighten up, reach maximum brightness then dim down. My guess is the whole process is over by 1/25,000 seconds.
In that tiny instant, it reaches the brightness of a 1,000 watt lamp.

That's faster than any mechanical shutter ever made , and for all practical purposes, its instantaneous.

[*isteve]

I've not seen any flash brand publish the actual timing for a single flash, but I was quoted a figure for the thyristors which power a well known brand of flash - and it triggers at 20 microseconds. That's 1/50,000 seconds. The actual flash strobe needs a bit of time to brighten up, reach maximum brightness then dim down. My guess is the whole process is over by 1/25,000 seconds.
In that tiny instant, it reaches the brightness of a 1,000 watt lamp.

That's faster than any mechanical shutter ever made , and for all practical purposes, its instantaneous.

Thats true for low power settings, but the xenon discharge cycle is longer than that at high power as it actually takes time to "burn out".

http://www.joesmalley.com/flashes/

Surprising huh? For comparo, Elinchrom Style 500's at full power are about 1/3200 which is fast for studio lights.

[GoldenWreckedAngle]

Some additional observations


Actually no I dont think this is quite the case. On any flash, the centre pin will send a pulse when the front curtain is fully open. The difference is what the other pins tell the flash to do.

If you have the other pins connected, the flash will know if its in HS mode (start when leading curtain moves, stop when trailing curtain closes) but this signal is ignored by a radio trigger, just as the trailing curtain signal for TCS is also ignored.

I think on Pentax the centre pin is disabled above the sync speed to prevent blackout in studio shots unless it detects an HS flash on the shoe. I think this is the difference.

However I dont know why you think the light source is continuous. Its as long as the single flash duration. Several milleseconds perhaps but no more. You will still get the trailing curtain blocking part of the image and this will look worse depending on relative flash/ambient exposure and flash duration.



PWs now come with a dedicated controller with all the pins (for Canon and Nikon). There is no reason you could not get them to "fool" the camera I guess.



This is a shutter limitation on SLRs. Without a leaf or electronic shutter you cannot do this using a single flash pop.

I'm right there with you. Everything I've ever read on flash tells me that it can't be done but apparently it can because here it is happening right before my very eyes.

And to be honest, the day I saw that video was the day I started really having problems with my Pentax flash system.

There is hope though. Here is a comment about halfway down the page asking about Pentax support and the official Radio Poppers response indicates that it's coming.

Question:
My Jaw drops - If I had a genie pop out of a bottle on me this little trick would make my top three list… but, I need Pentax support, please.

I heard a rumor that the poppers worked on Pentax bodies even though it wasn’t officially supported. If I have to switch camera systems to shoot these I’m telling you right now it’s a done deal but it sure would be nice if these would “unofficially” work with my Pentax bodies. Can anyone verify that?

RP Answers:
The P1 units won’t do this trick, but they do “unofficially” work with Pentax. The PX units are required for this trick and they currently absolutely will not work with Pentax - however, Pentax support is just a software update away and it’s in process. We expect Pentax support in the near future - we just need to complete a software profile that will optimally handle the timing and “language” of Pentax.

This goes also for Sony and Olympus.

[GoldenWreckedAngle]

Here is Radio Popper's condensed explaination:

Coolness! But … how do you get these flashes to behave like a constant light source? I thought they did a virtually instant power dump the moment they’re triggered … didn’t realise it was electronically possible to slow down the dump …

RP EDIT:
It’s like magic. We’ll see how the “compatible gear list” plays out, but some flash tubes burn longer at a fairly constant rate. Some burn very short and won’t play in this new way, but some of the particularly less expensive studio and strobe units out there - it turns out - are perfect for this trick.

[*isteve]

Here is Radio Popper's condensed explaination:

Coolness! But … how do you get these flashes to behave like a constant light source? I thought they did a virtually instant power dump the moment they’re triggered … didn’t realise it was electronically possible to slow down the dump …

RP EDIT:
It’s like magic. We’ll see how the “compatible gear list” plays out, but some flash tubes burn longer at a fairly constant rate. Some burn very short and won’t play in this new way, but some of the particularly less expensive studio and strobe units out there - it turns out - are perfect for this trick.

You give far too much credence to web-nerds who are trying to sell something.

Firstly, read this.

http://www.joesmalley.com/flashes/

You will notice that some third party flashes have durations close to the sync speed of some cameras. Hence all you need to do is find a way to detect the trigger point for the first curtain start which triggers HSS (they add an extra pin) and you can shoot at 1/8000 without HSS on the flash, but so what?

This ONLY works at full power, and only on SOME flashes, and you do NOT get even illumination across the whole output duration. No OEM flash or studio light will work, so this is a pretty lame product IMO. The only use I can see for this is that you can get more power out of the flash because its not strobing like in HSS mode. However it cant stop motion any better than the camera.

Secondly, Pentax will only send a leading curtain open signal if it detects a flash mounted which is set in HSS mode. Hence they will need to make a special version of their trigger which will "fool" the camera. Since they probably have not got a clue how to do this (they dont know the protocol and I doubt they would be bothered) I dont expect you will ever see a Pentax version. (And this is Pentax' fault?!?!?!?)

Thirdly, conventional flash techniques (a la Strobist) when used well can achieve amazing things and work just dandy with Pentax flashes. Why are you so concerned with left field oddities which are cool to talk about but can usually be achieved by more conventional means?

Incidentally, the same effect could probably be achieved using an HSS shoe mounted flash, as long as your slave flash has a light sensor and a setting which ignores the pre-flash. You can set this on the AF540FGZ but the flash duration would be too short anyway.

[GoldenWreckedAngle]

I respectfully counter that you seem to be stuck on convention so rigidly that you are too quick to dismiss innovation.

Conventional means are wonderful. I study and grow in my use of convention every single day, especially strobist conventions, but things-they-are-a-changing. I simply refuse to accept that it has to be the way it is. The conventions we are "stuck with" today have moved a long way from the conventions of the last decade or two as people have pushed the envelope. We wouldn't get very far if it weren't for individuals sporting a determined dissatisfaction with the way things are.

The Radio Poppers are changing the industry. Most of the current explosion in radio trigger technology can be traced to the fact that they finally ran the proverbial 4 minute mile last year with radio triggered HSS. The Radio Popper engineers have developed a phenomenal product line much loved by a lot of the top talent in the industry including Mr. Strobist himself, David Hobby.

In fact, the Pocket Wizard Flex seems to have been a direct response to the Radio Popper innovation and it seems to work just as well. Here is the Flex pulling the same stunt in the hands of a user who is not making a dime on them. This whole technique is kind of a side benefit to the primary goal of the engineers but it's one that will see a lot more development in the future, I'm sure of it.

I respect your opinion a lot. I get the impression that you have probably forgotten more than I know, but you are making up limitations in your head based on your extensive experience and well educated preconceived notions. Healthy skepticism is a virtue but so is an open mind. Please, let down your guard, and set aside your neutral density filter methods for a second, and try to wrap your mind around the possibilities.

The Radio Poppers appear to be intercepting the pre-flash info and are triggering the strobe before the front curtain opens so that it is already at its brightest when the first shutter opens. I looked at your link the first time you posted it, and again just a moment ago, but I don't see any studio strobes on it. Many studio strobes, particularly the cheaper ones such as the popular Alien Bees, have fairly long and consistent burn times that will evenly cover a 1/1,000 or longer exposure before they "flame out." Some strobes, like the one being used in the link I posted above, appear to actually burn longer at lower power, which again, completely goes against all conventional speedlight wisdom, I know.

So, it's conceivable that we might even see specialized studio strobes engineered for longer burn times as a direct result of this discovery, effectively creating an adjustable, high powered, short burst, "continuous" light source as one answer to the limited mechanical shutter sync speeds we are stuck with right now. Wouldn't that be a hoot?

---

Last edited by GoldenWreckedAngle; 07-07-2009 at 04:45 PM.

[*isteve]

I respectfully counter that you seem to be stuck on convention so rigidly that you are too quick to dismiss innovation.

Shucks 13 years with IBM R&D and 3 innovation awards all for nothing? Damn! Or maybe I just have higher standards?

I just look for ways to do what I want using what I have instead of moaning about it. And when did I mention ND grads, or for that matter any other flash technique I may or may not use? You must be confusing me with someone else.

Now I do know how Radio Poppers and PW Flex works, thankyou. They just dont make them for Pentax. And thats Pentax's fault? Last I looked they dont make them for Oly either. Bad Oly! Why dont we have 100 posts complaining about Pocket Wizard instead? Lazy so and sos. They are the only reason you dont have this wonderful feature.

I would LOVE a PW Flex, then I could use PTTL outdoors on all three of my strobes and use HSS. Yes, every pro from Aberdeen to Xanadu is buying one FOR THAT REASON. Now I can use a radio transmitter to place the flash close to the subject and darken the background using a fast shutter speed. Wow. Yes I would love that.

But at no time were we talking about that.

We were talking about the fringe benefits when used with SOME non HSS strobes.

I dont care whether you accept the limitations or not, but since they most certainly DONT work with all cameras/flashes/power settings I wont be throwing away my Elinchrom BXs (1/3200s) and buying a 1DS with some cheaper lights.

If you want someone to build a studio strobe with an HSS feature then be my guest - it still wont freeze motion. However the solution as used on HS flashes (short high speed pulses) could be emulated on studio lights using multiple capacitors, but I really think this is of limited use in a studio.

The real solution is better electronic shuttering in the camera. In the meantime, enjoy having HSS on your Sigma.

Anyway, since you seem to have convinced yourself that I dont understand innovation and that I am only telling you stuff to spoil your fun, I will leave you to it and wish you luck.

[GoldenWreckedAngle]

Anyway, since you seem to have convinced yourself that I dont understand innovation and that I am only telling you stuff to spoil your fun, I will leave you to it and wish you luck.

Well, now you are putting words in my mouth, or thoughts in my brain anyway. Your IBM credentials are impressive, (even if IBM hasn't made a camera or flash in a while ). Your intelligence comes through in most of what you write so it's probably my loss that you don't want to continue this discussion.

I've learned quite a bit from stubbornly disagreeing with you though so if you change your mind I will try to change my tone to something that hopefully will find you more receptive. I've read some of my earlier comments and I was in pretty rare form, but at least that form (hand wringing) is rare for me. I wasn't being entirely fair to Pentax but popping the cork helped me sort through my growing list of frustrations once my initial "flash" tapered off.

It would be nice to end this miserable thread on a more positive note surrounding some of the high points, namely ways to use the current Pentax flash system more effectively and some of the positive things the future may hold.

So back to the Radio Popper "hypersync" trick.

Here are the White Lightning Strobe specs listing both the T.1 and T.5 flash duration times. It looks to me like it's possible to get consistently well lit shots above 1/1000 every time with the Radio Poppers and White Lightnings.

The Radio Poppers would require an on camera HSS master controller such as an HSS enabled flash. I'm not sure if Pentax makes an infrared control unit like Canon or Nikon's but that is all they would need. I'd say the chances of a Pentax version of the Radio Poppers is at least as promising as the ongoing hope for a Pentax full frame or the rumored Paul Buff designed Einstein and Alien Bees Max strobes (with multiple capacitor banks incidentally - wonder if they could... ah, never mind, HSS is not what they are designed for). Still, stranger things have happened.

[GoldenWreckedAngle]

Shucks 13 years with IBM R&D and 3 innovation awards all for nothing? Damn! Or maybe I just have higher standards?

I just look for ways to do what I want using what I have instead of moaning about it. And when did I mention ND grads, or for that matter any other flash technique I may or may not use? You must be confusing me with someone else.

Now I do know how Radio Poppers and PW Flex works, thankyou. They just dont make them for Pentax. And thats Pentax's fault? Last I looked they dont make them for Oly either. Bad Oly! Why dont we have 100 posts complaining about Pocket Wizard instead? Lazy so and sos. They are the only reason you dont have this wonderful feature.

I would LOVE a PW Flex, then I could use PTTL outdoors on all three of my strobes and use HSS. Yes, every pro from Aberdeen to Xanadu is buying one FOR THAT REASON. Now I can use a radio transmitter to place the flash close to the subject and darken the background using a fast shutter speed. Wow. Yes I would love that.

But at no time were we talking about that.

We were talking about the fringe benefits when used with SOME non HSS strobes.

I dont care whether you accept the limitations or not, but since they most certainly DONT work with all cameras/flashes/power settings I wont be throwing away my Elinchrom BXs (1/3200s) and buying a 1DS with some cheaper lights.

If you want someone to build a studio strobe with an HSS feature then be my guest - it still wont freeze motion. However the solution as used on HS flashes (short high speed pulses) could be emulated on studio lights using multiple capacitors, but I really think this is of limited use in a studio.

The real solution is better electronic shuttering in the camera. In the meantime, enjoy having HSS on your Sigma.

Anyway, since you seem to have convinced yourself that I dont understand innovation and that I am only telling you stuff to spoil your fun, I will leave you to it and wish you luck.

By the way, my initial rant had nothing to do with me not being able to freeze motion. I can see where you came away with that impression, but it was actually more about an overexposure problem I ran into when switching between motion blur and stop action when I unexpectedly hit a 1/90 max sync speed in rear curtain mode.